The stepper motor is controlled by a digital signal. If the pulse signal changes too quickly, the Stepper Motor will follow the no-on signal change due to the damping effect of the internal reverse electromotive force. The magnetic reaction between the rotor and the stator will follow the change Lost step, on the other hand, the faster the angle to accelerate, but also to overcome the greater load inertia, lack of torque will also lead to stepper motor stall. Must use the acceleration and deceleration approach to solve this problem. That is, when the stepper motor starts, to give the gradual increase in the pulse frequency, deceleration pulse frequency needs to be gradually reduced. This is what we often say "acceleration and deceleration" method.

Most of the stepper motor PLC control, PLC control stepper motor acceleration and deceleration is usually used slope mode, acceleration and deceleration of the slope is symmetrical. Users only need to set the acceleration and deceleration time can change the slope.

Blue line acceleration and deceleration time of 200ms, red line acceleration and deceleration time of 400ms, relatively blue line efficiency is higher, the red line running more gentle, the user needs to select the acceleration and deceleration method, usually acceleration and deceleration time is short Greater torque support.

Most of the PLC also has a segmented pulse frequency function, that is, the speed is divided into three sections were set acceleration section, uniform segment, deceleration section, so that acceleration and deceleration can be asymmetric, to meet some need to quickly start slow stop, or slow start Fast stop device requirements.

Individual powerful PLC settings can be achieved segmented curve control, in the textile machine, embroidery machine, and CNC machine control system, often also use this operation to calculate the acceleration and deceleration curve.

There are still some of the equipment on the stepper motor control is the use of single-chip control, this type of equipment is often small size, low price, but also need stepper motor and controller small size, low cost. Therefore, the excellent curve design can release the load changes in the process of inertia, in a certain range to help users achieve this goal. There are users that every millisecond fixed plus a pulse design method is the most gentle, in fact, this is unrealistic, it is impossible from 0 to 10K frequency changes to write 10,000 lines of instructions, and acceleration and deceleration time is not good control.

The easiest way is this:

(1) is the highest frequency of the curve, C is the starting frequency, E is the natural number, A is the slope (reference value 1, the greater the value, the more gradient the curve gradient), X for the amount of change (reference value 0.5), B is a constant (5,10,15 can be, the greater the value, the more gradient curve)

Through the above formula can be drawn Y, you can build an excel table, X from 0 to change, each time +0.5, and then calculate Y, until Y close to the maximum frequency. It is well known that the conventional 57HB stepper motor (24V drive) is difficult to accelerate to 2000 rpm in 500 milliseconds, but it is easy to implement with the S curve.